1. Field of the Invention
This invention relates to metal working and more particularly to means to assemble and relatively position plural work parts.
2. Description of the Prior Art
The central feature of the cylinder lock is a rotatable mounted plug or cylinder. In the locked position, a number of pin tumblers of different lengths are pressed down by springs to engage with holes in the cylinder, thereby preventing the plug/cylinder from rotating. When the key is inserted into the lock, the pin tumblers are raised by exactly the correct amount to bring their tops flush with the outer surface of the cylinder. The cylinder/plug is then free to rotate when the key is turned. The cylinder actuates the bolt, so that the door can be opened. If the wrong key is inserted, it will not raise all or any of the tumbler pins to the correct height, and the cylinder/plug cannot be rotated.
When a locksmith must repair or re-key a lock, replacing the pins and springs, he often needs to use several tools simultaneously. He must also work with very small pins and springs which fit into the small bores of the new lock cylinder. In order to do this he uses a vise to hold the cylinder or awkwardly holds all pieces in his two hands. Frequently, while manipulating the many pieces, the pins and springs fall out of their chambers before they can be locked into position.
In order to solve this problem, Schlage in U.S. Pat. No. 3,664,007 discloses a cylinder loading tool which utilizes three pieces: a rod with an elongated slot and axial pin holes, a sleeve, and a slide. In use, the rod is loaded with pins and springs., the springs extending outward slightly from the pin holes. The slide is urged forward in the slot and pushes down each spring as it reaches it. Once a spring is pushed down, the sleeve is positioned over it, holding the pin and spring in the hole. When all springs and pins are loaded and being held in place by manually holding the sleeve in the correct position, the cylinder is slipped over the rod, displacing the sleeve and covering the pins. The cylinder is then turned to release the springs and pins into the appropriate pin holes in the cylinder.
However, it is difficult to correctly judge the correct distance to insert the rod to insure that the correct pin goes into each predetermined pin hole. Even when the correct position is determined, it is difficult to keep the correct alignment while turning the rod in the cylinder to release the pins. Because the locksmith must hold the cylinder with one hand and the sleeve with another hand, he is not able to manipulate the slide. He needs an extra hand or a vise in order to smoothly use Schlage's tool--one hand to hold the cylinder, one hand to hold the rod and move the slide, and a third hand to position the sleeve.
There is, therefore, a need for a lock cylinder loading tool which quickly and easily lines up the pins in the correct cylinder holes and does not require the aid of another person to load the pins and springs into a lock cylinder.